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jacket_fan · 03-05-2010, 07:54

As we search for available cats, many do not have one of the mandatory pieces of equipment - air conditioning. We will be spending time in the Caribbean and hope to have visitors from the states staying with us. I am in agreement that air conditioning is worth the weight penalty for passenger comfort.

We are looking at some older cats and am curious how difficult and expensive it is to add air conditioning to cats in the 38-45 foot range. I have looked at the CruiseAir website and looked at some diagrams as to what is involved in a marine air conditioning system.

If I were to have someone install A/C on an older St. Francis or a Privilege, or similar cat, what sort of costs should I expect to pay? Just some sort of ballpark estimate. I know it is not $5,000, but is $10k, $20k or more?

cliffdykes · 03-05-2010, 08:11

Quote:

Originally Posted by jacket_fan

As we search for available cats, many do not have one of the mandatory pieces of equipment - air conditioning. We will be spending time in the Caribbean and hope to have visitors from the states staying with us. I am in agreement that air conditioning is worth the weight penalty for passenger comfort.

Sorry - I'm not in agreement that a/c is worth the weight penalty for passenger comfort. There's a constant breeze in the Caribbean so as long as you've got opening hatches forward and aft, a/c is certainly not compulsory.
Also, it's unnecessary weight, complexity and expense; and running the generator to power it pollutes the atmosphere and annoys your neighbours.
So do us all a favour and do without

Cheers
Cliff

MarkJ · 03-05-2010, 08:22

Quote:

Originally Posted by cliffdykes

. There's a constant breeze in the Caribbean so as long as you've got opening hatches forward and aft, a/c is certainly not compulsory.

I agree with Cliff except for marinas.
If you use marinas a bit then it can get quite warmish as you boat is never head into the wind.

jacket_fan · 03-05-2010, 09:26

Sorry Cliff, we will have air conditioning on our cat. When my lovely life partner requires it, so it shall be.

Besides, there are times when you have to button up for rain, or the anchorage you are in has little if any breeze, or myriad other reasons for wanting the comfort of A/C. Especially if you have guests on board who are not used to the humid tropical nights.

Sailmonkey · 03-05-2010, 09:37

Tell us more about the system you'd like to have.
Iddividual controls for the cabins?
do you need a generator?
do you want to cool the whole boat or just the cabins?

There are several ways to approach this, and as the complexity increases so does the cost. It would be possible to chill just the aft cabins (or cabin) for less than 5k if you do the install yourself with a self contained unit to be run off of shore power. Or assume you need a generator capable of supporting the whole thing that relies on (I'll assume a 4 cabin for argument) 4 units for the cabins and a monster for the salon/hull area. a 12kw gen would handle this type of load.
just rough guess based on past experience would put this sort of thing upwards of 25-30k for all the equipment and the install.

Strygaldwir · 03-05-2010, 10:38

One of the major issues is supplying power for the AC unit. If it is going to be used outside a marina anything that will cool a cat in the over 37 foot range is going to most likely require a genset. In most cases, you're going to want a genset that is diesel driven. These tend to be heavy. In the low end of the range, say 37 - 39 foot. The 400+ pounds will place a significant strain on your carry capacity. In the 42+ range, no too much of an issue.

I think an installed 5kw diesel genset would cost what, about $10k. Significantly less if you do the installation yourself. Then the AC unit, another $18k or so. Haven't looked since I decided I could not afford the weight penalty and I am on the lower 37 foot range.

jacket_fan · 03-05-2010, 11:32

Thanks for the input.

I am trying to work out all of the trade-offs versus requirements. A genset and sufficient A/C system is a requirement. Again, that is from my wife. She does not care how much it weighs, whether it costs additional money, is loud, smelly or is complicated.

So if it is $25k to $30k, we need to be able to budget for it and make sure it is feasible. If there is an existing genset, you would end up sizing the A/C you want to install not to exceed its load capability. Or go another $10k for a more capable genset.

I am more than willing to do all of the installation myself, and save some money there.

One of the more interesting cats out there that we can afford is an older Manta. At either 40 or 42 feet, it came with installed air conditioning. Therefore, it is feasible to have A/C on a cruising cat in that range.

Sailmonkey · 03-05-2010, 11:45

Quote:

Originally Posted by jacket_fan

One of the more interesting cats out there that we can afford is an older Manta. At either 40 or 42 feet, it came with installed air conditioning. Therefore, it is feasible to have A/C on a cruising cat in that range.

Anything is feasible, provided you have the cash to make is feasible. If you need A/C to get out there you'll find a way. Being the cheapskate that I am, I'd look at cooling individual cabins and running a much smaller and less expensinve system.

Jeannius · 03-05-2010, 11:55

Quote:

Originally Posted by jacket_fan

As we search for available cats, many do not have one of the mandatory pieces of equipment - air conditioning. We will be spending time in the Caribbean and hope to have visitors from the states staying with us. I am in agreement that air conditioning is worth the weight penalty for passenger comfort.

We are looking at some older cats and am curious how difficult and expensive it is to add air conditioning to cats in the 38-45 foot range. I have looked at the CruiseAir website and looked at some diagrams as to what is involved in a marine air conditioning system.

If I were to have someone install A/C on an older St. Francis or a Privilege, or similar cat, what sort of costs should I expect to pay? Just some sort of ballpark estimate. I know it is not $5,000, but is $10k, $20k or more?

You are absolutely right to want air conditioning. It'll makes a massive difference to your enjoyment of the boat in the Caribbean. Even if you don't need the a/c for cooling, you do want it to dehumidify the boat.

I think you would be best off finding a boat that already has it installed. It is expensive and difficult to retrofit properly.

Strygaldwir · 03-05-2010, 11:55

If I had an AC requirement, I not put it in a cruising catamaran of less than 40 feet. My issue, as I implied, is one of weight. We found that there were SO many things we just had to put aboard when we were cruising. When we stopped cruising and took all that extra stuff of and found we our cat was in actuality a very fine sailing vessel as opposed to the "dog" I had been known to call it. We found that even in our "dog" configuration, we out sailed a Manta 42 in our relative cruising configuration.

But, I understand completely about requirements! Manta is a lovely boat, your wife would most likely be VERY happy with being aboard, and with A/C, water maker, ice maker and built in solar panels it makes quite a platform.

djmarchand · 03-05-2010, 12:02

First the costs:

You are going to need two 16,000 BTU units at about $3,000 each for the unit, pump thru hulls, duct, etc. Anything less and you won't be cool during the day.

Each A/C unit will draw about 16 amps, maybe less together as they will probably share a water pump">raw water pump, but figure 32 amps anyway. It will take a whole lot more than that to start them.

You could get by with 5 KW genset if you are careful, never start both at the same time and don't use a hair dryer or other high wattage appliance at the same time that both A/Cs are running. Most people would install an 8 KW genset but note the caution below.

A 5 KW NextGen will cost about $6,000 and an 8 KW Northern Lights will cost about $10,000. Those are the extremes of what I would install. Thruhulls, strainers, hoses, muffler, wire and circuit breakers will add about $1000.

So you are looking at $13-17,000 in equipment and parts if you do all of the work yourself.

The caution:

Gensets in the middle of the night when the A/C is mostly cycled off, have ZERO load on them. That isn't good as the engine is running at WOT to maintain frequency but has no external load. So unburned diesel gets on the cylinder walls, builds up a glaze, which allows blowby and low compression. Hard starting and oil consumption result. The fix is technically easy- pull the engine, tear it down and run a hone through the cylinders. But it will be costly.

There is one solution, but it will take $ and some operational control to make it work. Mastervolt recently announced a new packaged genset and inverter which acts as a "hybrid". When the loads are low, the inverter powers the appliance by drawing from the connected house battery. When the load increases or the batteries get depleted, the genset starts up automatically and powers the load and recharges the battery. The inverter also bootstraps the genset when big motors like an A/C start.

This unit is probably quite expensive. It based on a genset that may be too small- 3 KW as I recall and is bootstrapped to a 2 KW inverter. During the middle of the day you will need both A/Cs running and they will consume about 4KW. Unless you have a huge battery bank to supply the difference the batteries will discharge trying to run the inverter to make up the difference. But at night all will work out as the A/Cs will cycle off mostly and the genset will have capacity to recharge the batteries. The genset will stay loaded, run efficiently and be happy.

This system could be made to work, but needs to be evaluated by someone who understands the Mastervolt product and how you will use it.

Or you could install a minimal 5KW genset and hope for the best. But let me quote the manager of Bayshore Marine, the Northern Lights dealer in Annapolis- "I make a nice living rebuilding gensets that return from a season in the Carribean.

David

YOGAO · 03-05-2010, 12:08

...the layout of the cat's storage areas. Getting the units in the right place, the thru-hulls for cooling water and the dump of the heated water, plus the vent placement, etc can be costly and hard to do after the boat's been built.

We had two 9K BTU Mermaid A/C units installed on our cat during the initial build. Cost was in the 10K range (I think - memory is starting to go). Add to that the cost of a genset (with its own placement, wiring and fuel supply runs, etc) and I would think you could be in the 20K range.

Back to beating a dead horse (going w/o A/C). Have you guys chartered down here? Will you be marina-hopping or anchoring out?

FWIW, our experience has been if you are anchoring out in virtually any anchorage, you will have wind. The rains don't last too long. Our guests have never complained about the heat (or at least they stopped after we threatened to strand them on an uninhabited beach

). Too hot? Jump in the ocean and cool off (a frequent afternoon activity for us)!

Fair Winds,
Mike

jacket_fan · 03-05-2010, 12:42

Just to clarify. We have chartered in the Caribbean. Actually, our charters have only been in the Caribbean. Which is why the wife will not be without A/C.

I understand real sailors don't what the cost, complexity and weight of gensets and air conditioners. I get it. But I am only half the equation. As a matter of fact, less than half the equation.

(We will be in the BVIs at the end of the month on a Moorings 46 for 8 glorious days. With air conditioning.)

David, I am curious about your post. It makes sense, but I had not thought that diesel would glaze up the cylinder walls. Although the compressor does not run all night, would the load from the air conditioner fans be enough load to reduce or mitigate the glazing? Or find something else to sequence to keep a load on the genset? Surely some smart person has come up with a way to prevent this problem without the complicated system you described.